Making hollow steel bars



May 8, 1928,

1,668,705 T S. WHEELWRIGHT MAKING HOLLOW STEEL BARS Filed June 21, 1927 2 Sheets-Sheet l T. S. WHEEL-WRIGHT MAKING HOLLOW STEEL BARS Filed June 21, 1927 2 Sheets-Shem 2 was Patented May 8, 1928.

UNITED STATES PATENT OFFICE.

THOMAS STEWART WHEELWRIGHT, OF RICHMOND, VIRGINIA.

MAKING HOLLOW STEEL BARS. I

Application filed June 21, 1927. Serial No. 200,364.

This invention relates to the manufacture of drawn hollow articles and is especially applicable-for making stay-bolt stecl, although it may be applied to many other purposes.

The invention consists essentially in the economical production of hollow ingots of predetermined internal and external dimen- 'sions, shape and smoothness, and then rolling or drawing such ingots down to the desired size; the ingots being made by casting metal, preferably but not necessarily ferrous metal, onto a metal core also preferably but not necessarily ferrous, and which.

becomes part of the article made. This invention is particularly used in the economigal production of steel bars for hollow stayolts.

In a patent, No. 1,618,142, February 15, 1927, I have described a process which is v especially applicable for making stay-bolt iron, which process consists essentially of building up a hollow fagot by arranging rods or bars around a hollow metal core, which core is filled with refractory material, heating the built-up fagot to a welding and rolling temperature, rolling the heated fagot down to the required size and section, and then removing the refractory from within the core.

I have discovered that I can improve the product by building up around the hollow metal core a jacket of rods parallel to and in contact with the core; with this exception, that in' the process covered in the aforesaid patent, practically the whole body of the fagot is built u of the rods, whereas in my new process I arrange only one or two rings of rods concentricallyaround a hollowmetal core. This core is then set in a mold; steel is poured into the mold around the hollow metal core and the'rods; the molten steel fusing and amalgamating with the hollow metal core and the rods'surrounding it, to form a homogeneous mass.

1 have found that by so combining the wrought rods with the cast steel I produce afinished rod of great tensile and torsional strength, and great vibratory value. In forming the molds I have found that it is economical to use the multiple mold system, similar to that described byJ. G. Webbi in his Patent No. 1,389,722. In using a system of this kind molds can be made at less cost, and they are more durable.

show profiles of the rolls.

In the accompanying drawings, which form a part of this specification, and in which like-numerals refer to like parts in the several views: Figure l is a detail in perspective of a mold section; Figure 2 is an end view of the same. Figure 3 is a plan of a series of molds; Figure 4 shows the same in part vertical section and part elevation. Figure 5 shows a core; and Figures 6 and 7 end views of the same. Figures 8 and 9 Figure 10 shows the method of removing the core.

In Figures 1 and 2 the numeral 1 indicates a mold section of a multiple ingot mold. The sections are so formed that when they are connected together, two adjacent sections form the mold in which the ingot is to be cast. For instance, in Figures 3 and 4, the sections 2 and 3 when placed together form the mold 6'; sections 3 and 4 when placed togethcr form the mold 7, and so on. On the top of the mold sections 2, 3, 4 etc. are placed a series of hot tops or pouring heads 8, 9, 10, 11, which are made of suitable refractory material, and which are connected together at points over the centers of each of the mold sections. These hot tops can be made in fewer sections if desired, but it is somewhat less expensive to make them in the separate sections as shown. When so made one hot top is connected with the next one by means of gates 12, 13, 14,.which connect together the basins 15, 16, 17, 18. These basins are connected with the interiors of the moldsby a number of gates 19, which are spaced around the centers of each mold and between these centers and the sides of the mold. The lower face of each hot top projects downward into the mold cavity. In the lower faces and between the gates in each one, are recesses 20 for seating the upper ends of the cores 21. The lower ends of these cores enter openings 22 at the bottom of each mold,

wvhich openings are formed by grooves 23 cast in the bottom of each mold section.

.The cores can yent downwards through the 'openings22, and they can also vent upwards 15, 16, 1'7, 18, are preferably large as shown in the drawings, so that they may form adequate "feeder-heads tor the ingots.

As in my previous practice, which is ox plained in my applications referred to herein I form the inner part of my cores of pieces of steel pipe or tubing of suitable size;

see Figure 5. These tubes are shown at 25. Each tube core I fill with refractory material, preferably similar to the material used in the hot tops; or of clean silica sand. The ends of the tube cores may be plugged as shown at 26in Figure 5 to prevent theescape of sand. As explained in myapplication,

Serial No. 137,469, it is important that the metal flow downwards from the hot -top basin into the mold without in its descent striking the side of the metal core, as it is apt by so. doing to buckle the core. It is important that the molten metal drop to the bottom of the mold and then rise evenly and uniformly up.around the core. This is provided for by the correct spacing of the gates in the under surface of the hot top; In order to add additional protection to the tube core I now surround the latter with an armour of small steel rods, as at 27, which rods are "held in place by suitable bands or wire ties 28. These rods are preferably of the same analysis, or approximately of the same analysis, as the steel which ispoured into the ingotsI These rods fill two very useful purposes, the firstof which is to protect the tube core from buckling should the hot metal come into contact with it in its descent, and the second of which isto add largely to the tensile strength of the finished bar. Referring to the protection afiorded to the tube core; should descending molten 'metalhit the rods on one side, they will as pand lengthwise, still keeping straight,

rather than buckle; and at the same time they will also protect the tube core: from the sudden application of the intense heat of the strength of molten steel.

Referring to the strength of the finished. barz-"it was expected, and it has been. proved, that the small steel rods become thoroughly fused with the molten steel. forming the ingot, and add' greatly to the the finished bar. The mblten steel passes between the rods and fills the interstices between the rods and the tube core, with which italso fuses, making one solid and integral ingot. However, upon making a section of the ingot, and even of the finished rolled bar, and polishing and etching the section, the presence of the 'steel bars surrounding the core may be seen.

In Figure 5 it will be seen that the steel bars do not extend to the end of the tube core. The projecting ends of the tube core form core prints which are set in the recesses 20 in the hot-tops and in the nings 22 in the bottoms of the molds. ig-

messes ure 6 shows in end elevation the tube core 25 surrounded by the steel rods 21 and packed with silica sand 29, As this sand in making the hot tops, which is usually asilica sand mixed with linseed oil and sawdust. This compositioh is rammed into the tube core around a vent rod 31, see Figure 7. The vent rod is removed after packing, and the composition core is baked in an oven. This composition core is easily removed from the in ot after casting. After ingots have set 'an partly cooled they are broken out; and the composition cores are removed. The centers of the, ingots are now packed with silica sand; the ingots are reheated, and they are rolled into the finished bar. In'Figures 8 and 9 are shown profiles of the rolls. In my Patent No. 1,618,142, I have explained that it is advisable to she e the passes in the form of a polygonal gure such as an octa on or hexagon, see Fi re 9; or in a modi ed octagonal form w ich I term a gothic, see Figure 8. The last ass I make of the usual shape, to give the hnished bar its circular section. The object of thepoly onal passes is to control, the bar the r01 ing, and to prevent-itsturniiig or twistin in its passage through thefliolls. The re eated ingot is 'introducedinto the first pass,'which will immediately'give it a polygonal form. The ingot is then fed to the second and succeed- In Figure '10, the end at the bar is shown I at Compressed air is-then furnished through a hose. 3'4 terminating in a brass tube 35 of {3 outside diameter, the bore 36 of the rolled bar now being of about 1' inside diameter. Y This tube 35', which is about the same length as the bar, is then introduced into the core hole in the latter, and air at a pressure of about 150 lbs. per

square inch discharged through the tube.

As the air tube 35 is advanced into the core hole in the revolving bar, the refractory material is loosened by the rapidly flowing air, and it is expelled from the core backward around the tube. This application of the use of the'compressed air is fully explanted-in my Patent No. 1,618,142.

' I have described my new process as it is applied to the making of hollow steel bars for use in the manufacture of staybolts; and

to the manufacture of hollow bars of steel;-

for it may beused in the manufacture of hollow articles or bars of other cast and wrought metals. v

I claim 1. 'The method of making hollow metal bars, which comprises surrounding a' hollow metal corev with, a parallel jacket of metal rods packin the hollow core with refractory materia casting an ingot around the core at a temperature to fuse with the said core; heating the ingot to" a rolling tem-,

perature; rolling the ingot to the desired dimensions; and removing the refractory core. a

2. The method of making hollow metal bars, which comprises surrounding a hollow metal core with a parallel jacket of .metal rods in contact with thecore; packing the hollow core with refractory material; casting an ingot around the core at a tempera ture to fuse with the said core; heating the ingot to a rolling temperature; rolling the ingot to the desired dimensions; and removing the refractory core.

In testimony whereof I hereunto aflix my signature. A

- THOMAS STEWART WHEELWRIGI'IT. 

